This application is related to the following pending applications being concurrently filed herewith and assigned to the assignee of the present invention:
This invention relates in general to an air conditioning unit and more specifically to a rooftop air conditioning unit for a vehicle such as a bus.
The most common approach for air conditioning the interior of a bus is to mount the air conditioning components on the roof of the vehicle. It has been the common practice in the industry to locate the compressor for the unit in the vehicles motor compartment so that it can be driven directly from the engine. The compressor, in turn, must be connected to the air conditioning unit by means of refrigerant supply and return lines. This requires running an extensive amount of piping through the bus between the engine compartment and air conditioner. The piping tends to sweat depending upon the atmospheric conditions inside and outside of the bus and therefore poses a constant danger to the bus structure and a nuisance to passengers seated beneath a sweating pipe.
In addition, in existing bus rooftop air conditioning units it is common to design the unit with an evaporator housing with integrated bottom drip pan, and an evaporator coil mounted into the housing. An evaporator lid is included to cover the housing. The same design principles apply to the condenser design where also a condenser housing, a condenser lid and the condenser coil is used. Due to this design, about 25% of the total cost of the unit is included into the housing and the housing lid.
It is therefore an object of the present invention to overcome the problems of the prior art described above, and reduce the overall cost of rooftop air conditioning units described herein.
It is another object of the present invention to provide an improved air conditioning unit that is mounted upon the roof of a bus or similar type of vehicle.
It is a further object of the present invention to provide an improved heat exchanger design for an air conditioning unit that is mounted upon the roof of a bus.
It is another object of the present invention to provide a heat exchanger design which obviates the need for multiple housings in a low profile air conditioning unit that is mounted upon the roof of a bus.
It is yet another object of the present invention to provide a novel heat exchanger design for a roof top air conditioning unit of a vehicle which reduces the number of parts, fasteners and assembly labor time.
These and other objects of the present invention are attained by a compact rooftop air conditioning unit for a bus or similar type vehicle that contains an electrical driven compressor and an inverter for regulating the electrical input to the electrical components contained within the unit. The evaporator coil of the unit is mounted in front of a condenser coil, and at least one cylindrical evaporator fan is mounted adjacent the evaporator coil upon a horizontally disposed shaft which, in turn, is rotated by an electrical motor. A drip pan is positioned beneath the evaporator coil and is arranged to pass the collected condensate into the sump of a pump housing through an inlet port.
The invention eliminates the need for the use of multiple housings in which the heat exchanger coils are mounted in that two tube sheets take over the function of the housing side wall with the evaporator drip pan closing the air handling box from the bottom and the unit lid closing the air handling box from the top.